Turbines have been around for a long time—windmills and water wheels are early examples. The name comes from the Latin turbo, meaning vortex, and thus the defining property of a turbine is that a fluid or gas turns the blades of a rotor, which is attached to a shaft that can perform useful work.

Prepositions: useful is used in useful for <purpose>, useful for <person> and useful to <person>. The words useful to are also found in construction such as It is useful to do, in which to marks an infinitive rather than being a preposition.